Add LOG_BASE_FIELD and LOG_EXTRA_FIELDS

lodge.py

@@ -17,14 +17,16 @@ def _get_log_level_from_env_var(logger_name: str) -> str:
 
 def _get_format():
     DEFAULT_LOG_ENV = os.environ.get("LOG_ENV", "PROD")
-    BASE_STRUCTURED = {
-        "message": "%(message)s",
-        "timestamp": "%(asctime)s",
-        "level": "%(levelname)s",
-    }
+    LOG_BASE_FIELDS = eval(
+        os.environ.get(
+            "LOG_BASE_FIELDS",
+            '{"message":"%(message)s","timestamp":"%(asctime)s","level":"%(levelname)s",}'
+        )
+    )
+    LOG_EXTRA_FIELDS = eval(os.environ.get("LOG_EXTRA_FIELDS", '{}'))
 
     if DEFAULT_LOG_ENV == "PROD":
-        log_format = json.dumps(BASE_STRUCTURED)
+        log_format = json.dumps({**LOG_BASE_FIELDS, **LOG_EXTRA_FIELDS})
     else:
         log_format = "%(asctime)s | %(levelname)s | %(name)s | %(message)s"
 

test_lodge.py

@@ -96,3 +96,31 @@ def test_set_format_on_dev(stream, monkeypatch):
     assert log_entry_splitted[-1] == " Here goes a message\n"
     assert log_entry_splitted[1] == " INFO "
     assert log_entry_splitted[2] == " testlog "
+
+
+def test_set_extra_fields_on_logging(stream, monkeypatch):
+    monkeypatch.setenv("LOG_EXTRA_FIELDS", '{"program":{"name":"testlog","version":"v1"}}')
+    with import_lodge() as lodge:
+        log = lodge.get_logger("testlog")
+        log.info("Logging with extra fields")
+
+    log_entry = stream.read()
+    log_structured = json.loads(log_entry)
+
+    assert log_structured["message"] == "Logging with extra fields"
+    assert "program" in log_structured.keys()
+    assert log_structured["program"]["name"] == "testlog"
+    assert log_structured["program"]["version"] == "v1"
+
+
+def test_set_base_fields_on_logging(stream, monkeypatch):
+    monkeypatch.setenv("LOG_BASE_FIELDS", '{"message":"%(message)s","anotherField":"yes"}')
+    with import_lodge() as lodge:
+        log = lodge.get_logger("testlog")
+        log.info("Logging other base fields")
+
+    log_entry = stream.read()
+    log_structured = json.loads(log_entry)
+
+    assert log_structured["message"] == "Logging other base fields"
+    assert log_structured["anotherField"] == "yes"